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3 years ago

Given the reactions

Chemistry

1 answer:

AlladinOne [14]3 years ago

6 0

Answer:

The answer to your question is: ΔH = 1637.8

Explanation:

Hess' law: This law states that the enthalpy change can be calculated even if it is not calculated directly.

"if a chemical change takes place by several routes, the overall enthalpy change is the same regardless the route".

Process

A) N2(g)+O2(g)—->2NO(g) Δ H= -180.5

B) N2(g) + 3H2(g) ——> 2NH3(g) Δ H= -91.8

C)2H2(g)+ O2(g) —-> 2H2O(g) Δ H= -486.6

The result must be:

4NH3(g)+5O2(g)—->4NO(g)+6H2O(g)

Turn letter B and multiply it by 2

4NH3 ⇒ 2N2 + 6H2 ΔH = 183.6

Multiply letter A by 2

2N2 + 2O2 ⇒ 4 NO ΔH = -361

Multiply letter C by 3

6H2 + 3O2 ⇒ 6H2O ΔH = -1459.8

Finally we add the equations up and simplify then:

4NH3 + 5O2 ⇒ 4NO + 6 H2O

And we add the ΔH = 183.6 - 361 - 1459.8

= -1637.8

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3 years ago

1.5 mol sample he occupies a volume of 2.5 L at a pressure of 14.7 atm what will be the pressure of a 1.5 mol sample of h2 gas u

Sergio039 [100]

Answer:

Under the same conditions, the pressure of a 1.5 mol H2 sample is 14.7 atm

Explanation:

Step 1: Data given

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Volume = 2.5 L

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Step 2: Calculate pressure of H2 gas

p(He) * V(He) = n(He) *R*T

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⇒ The number of moles He = 1.5 moles

⇒R = the gas constant = 0.08206 L*atm/mol*K

⇒T = The temperature

p(H2) * V(H2) = n(H2) *R*T

Since the conditions are the same:

-Volume of both samples is 2.5L

- Temperature for both is the same

- the gas constant for both is the same (constant)

- The number of moles for both samples is 1.5 moles

Since all the factor are the same, the pressure will also be the same = 14.7 atm

⇒ Volume of the h2 sample = 2.5L

⇒ The number of moles H2 = 1.5 moles

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4 years ago

The question is on the picture.

nydimaria [60]

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3 years ago

4. The reaction of silver nitrate and potassium bromide yields silver bromide and potassium nitrate. If

Hatshy [7]

Answer:

1.) AgNO₃

2.) 0.563 moles AgBr

Explanation:

The limiting reagent is the reagent that is used up completely during a reaction. It can be identified by calculating which reactant produces the smallest amount of product. This can be done by determining the number of moles of each reagent (via molarity conversion). and then converting it to moles of the product (via mole-to-mole ratio).

AgNO₃ (aq) + KBr (aq) ---> AgBr (s) + KNO₃ (aq)

Molarity (M) = moles / liters

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? moles = 0.563 moles

KBr

75.0 mL / 100 = 0.750 L

0.800 M = ? moles / 0.750 L

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In this case, there is no need to use the mole-to-mole ratio because all of the coefficients are one in the reaction (the amount of the limiting reagent used is the same amount of product produced). Since AgNO₃ produces the smaller amount of product, it is the limiting reagent.

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